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To bore or not to bore ( Intake, that is ) by RayOtton
Started on: 09-11-2013 01:16 PM
Replies: 17 (437 views)
Last post by: raysr11 on 09-14-2013 01:58 AM
RayOtton
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Report this Post09-11-2013 01:16 PM Click Here to See the Profile for RayOttonClick Here to Email RayOttonSend a Private Message to RayOttonEdit/Delete MessageReply w/QuoteDirect Link to This Post
I recently purchased a modified upper intake from a fellow member ( thanks Jeff, it was a pleasure ). The modification is the "Dawg style intake" where the restrictive part of the upper plenum throat is cut out and a round piece of aluminum is welded in it's place to enlarge the passage and increase airflow.The EGR port is intact and will be hooked up.

I have the tools to bore the intake out to 56 or 57MM but I don't have the resources right now to buy a bored out throttle body. I'd rather not install it and later have to remove the new intake for modification so the question is, can I bore it out now, install it and add the larger throttle body later?

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MulletproofMonk
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Report this Post09-11-2013 02:48 PM Click Here to See the Profile for MulletproofMonkClick Here to visit MulletproofMonk's HomePageSend a Private Message to MulletproofMonkEdit/Delete MessageReply w/QuoteDirect Link to This Post
I don't see why not. The throttlebody opening will be the restriction at that point...
BTW, this is pretty good pricing on a bored throttle body. $135 if you send them one. http://www.throttlebodys.com/FieroTBs.htm

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[This message has been edited by MulletproofMonk (edited 09-11-2013).]

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raysr11
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Report this Post09-11-2013 02:48 PM Click Here to See the Profile for raysr11Send a Private Message to raysr11Edit/Delete MessageReply w/QuoteDirect Link to This Post
Yes you can. I have done it both ways. You will want to wait until you have your bored out TB before having the chip remade however. It's not a big deal at all though to r& r the upper intake. Personally I wouldn't bore the manifold until I had the TB.
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Raydar
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Report this Post09-11-2013 06:33 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
I would go ahead and do the boring. It shouldn't make a difference.

Having said that, Oreif found a larger (63mm?) throttle body that will work on our engines. I don't know where the thread is any more, however.
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RayOtton
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Report this Post09-11-2013 08:24 PM Click Here to See the Profile for RayOttonClick Here to Email RayOttonSend a Private Message to RayOttonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ok, thanks for the link. I'll check it out.

BTW, I don' think I'd need a 63Mm Throttle body. All I plan to do is the intake and exhaust porting to go along with already installed UD pulley, the cat delete and eventually, 1.6 rockers.

Thank WILL be it, I swear.


But what's this about a chip change?

From what I've read here there's no need for a chip upgrade with these particular improvements.
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ConvictedRedneck
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Report this Post09-11-2013 09:49 PM Click Here to See the Profile for ConvictedRedneckClick Here to Email ConvictedRedneckSend a Private Message to ConvictedRedneckEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Raydar:

Having said that, Oreif found a larger (63mm?) throttle body that will work on our engines. I don't know where the thread is any more, however.



Anyone have more info on this??

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Grantman
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Report this Post09-11-2013 10:02 PM Click Here to See the Profile for GrantmanClick Here to Email GrantmanSend a Private Message to GrantmanEdit/Delete MessageReply w/QuoteDirect Link to This Post
I bought my bored out TB from Steve Monroe. Great guy to work with and the TB he sent me looked absolutely like new.

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Francis T
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Report this Post09-11-2013 10:43 PM Click Here to See the Profile for Francis TClick Here to visit Francis T's HomePageClick Here to Email Francis TSend a Private Message to Francis TEdit/Delete MessageReply w/QuoteDirect Link to This Post
When we did our flow-bench testing on our intakes we did it with a stock TB opening and the data/numbers -{ http://trueleo.com/Fierointake.htm } confirmed that the stock intake was main CFM limiter and not the TB. Most of our customers use stock TBs the including me.

I built a highly modified 2.8 and it has a stock TB on it. - the red 2.8 on the cradle shown here- Now I may go with a larger TB after a get some dyno numbers on that engine.

Basically, if you can find a bored out Tb real cheep, get it, if not more than likely a stock TB will do fine. Save your money for something more cost effective.

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RayOtton
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Report this Post09-12-2013 07:55 AM Click Here to See the Profile for RayOttonClick Here to Email RayOttonSend a Private Message to RayOttonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks you for the info.

Guess I'll leave it as is.
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MulletproofMonk
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Report this Post09-12-2013 08:57 AM Click Here to See the Profile for MulletproofMonkClick Here to visit MulletproofMonk's HomePageSend a Private Message to MulletproofMonkEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hopefully you have done work on the exhaust too. No good putting air volume into the motor that you can't get out...
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RayOtton
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Report this Post09-12-2013 09:42 AM Click Here to See the Profile for RayOttonClick Here to Email RayOttonSend a Private Message to RayOttonEdit/Delete MessageReply w/QuoteDirect Link to This Post
" All I plan to do is the intake and exhaust porting to go along with already installed UD pulley, the cat delete and eventually, 1.6 rockers."
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Report this Post09-12-2013 09:53 AM Click Here to See the Profile for BruceptsClick Here to visit Brucepts's HomePageClick Here to Email BruceptsSend a Private Message to BruceptsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Some reading for you

http://www.fiero.nl/forum/Forum2/HTML/118417.html

I posted up some flowbench numbers testing a bored TB and DAWG modified intake as well as the stock parts. I have not updated that post in awhile though so it's not at the "top of the list". Still looking for a stock air cleaner housing so I can test it also, as well as test some various air filters. So far nobody seems to want to sell a V6 air cleaner housing?


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"There is no more formidable adversary than one who perceives he has nothing to lose." - Gen. George S. Patton
http://www.flowbenchtech.com

[This message has been edited by Brucepts (edited 09-12-2013).]

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Report this Post09-12-2013 10:49 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you want to bore out the intake manifold now, then go for it. It won't hurt anything.
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raysr11
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Report this Post09-12-2013 02:23 PM Click Here to See the Profile for raysr11Send a Private Message to raysr11Edit/Delete MessageReply w/QuoteDirect Link to This Post
As for the chip, if you flow more air with the opened up manifold it will change your a/f ratio. I had a modified intake like yours except with egr delete and a bored TB. It had a bad tip in problem that I was never able to solve. The modified "stock type" manifold that West Coast Fiero's sell has a seventh injector to compensate for this issue, http://www.westcoastfiero.com/intake/intake.html. I agree that the stock TB would be the best way to go.
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Report this Post09-12-2013 02:47 PM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by raysr11:

As for the chip, if you flow more air with the opened up manifold it will change your a/f ratio. I had a modified intake like yours except with egr delete and a bored TB. It had a bad tip in problem that I was never able to solve. The modified "stock type" manifold that West Coast Fiero's sell has a seventh injector to compensate for this issue, http://www.westcoastfiero.com/intake/intake.html. I agree that the stock TB would be the best way to go.


Were you too rich or too lean on tip in?
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Report this Post09-12-2013 04:29 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm guessing it went lean. When you enlarge the throttle valve, it lets air rush in the intake faster when you step on the go-pedal. As a result, you need the fuel to rush in faster as well, or the engine will go lean when you hit the gas.

I had a similar problem after installing a Trueleo intake with a Buick GN (59mm) throttle body on my engine. It went lean on acceleration, enough to make the engine stumble. I fixed the problem by making the acceleration enrichment (in the ECM programming) more aggressive.
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Report this Post09-12-2013 08:51 PM Click Here to See the Profile for Francis TClick Here to visit Francis T's HomePageClick Here to Email Francis TSend a Private Message to Francis TEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by raysr11:

As for the chip, if you flow more air with the opened up manifold it will change your a/f ratio. I had a modified intake like yours except with egr delete and a bored TB. It had a bad tip in problem that I was never able to solve. The modified "stock type" manifold that West Coast Fiero's sell has a seventh injector to compensate for this issue, http://www.westcoastfiero.com/intake/intake.html. I agree that the stock TB would be the best way to go.


We found the stock chip to work fine on 2.8s with using our intakes and headers and no other engine mods. I'd put it on a wide band before you shell-out money for a chip.

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raysr11
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Report this Post09-14-2013 01:58 AM Click Here to See the Profile for raysr11Send a Private Message to raysr11Edit/Delete MessageReply w/QuoteDirect Link to This Post
I never found out if it was lean or rich but I'm sure it was leaning out. It just fell on it's face at tip in. I fought it for a year and gave up and put a stock TB and manifold on and it runs dramatically better than it did modified. Gm tuners was helping me with it but I kept running across other issues. The chip I have now is modified quite a bit. At last resort we were going to check what the 02 sensor was reading but I threw in the towel and my tune time ran out. It felt exactly like a carb with a bad accelerator pump.

[This message has been edited by raysr11 (edited 09-14-2013).]

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